High-quality shielded diffusion method for heavily doped silicon substrates

Abstract

A high-quality shielded diffusion method for heavily doped silicon substrates belongs to the field of semiconductor technology. In order to solve the inherent defects of the heavily doped diffusion process and improve the uniformity of the substrate material sheet, the method includes putting the original silicon single crystal into FSI for automatic cleaning Inside the machine, it is cleaned with acidic etching solution and standard SC-1 / SC-2 / sulfuric acid cleaning solution; high-temperature dry oxygen oxidation process is used to form dense SIO on the surface of the silicon wafer 2 Layer, and determine different thickness gears according to different product requirements, the thickness is set between; photolithography and corrosion; N + Pre-diffusion, put the silicon wafer into a horizontal automatic high-temperature diffusion furnace, use a high-temperature constant source diffusion process, and use a phosphorus source as a doping source; N + For main diffusion, silicon wafers are placed in a horizontal automatic high-temperature diffusion furnace, using high-temperature push junction conditions, that is, the temperature is 1280 ° C ~ 1310 ° C, and the operation is performed by placing the wafers on the opposite side and entering and exiting the furnace with fast entry and slow exit; phosphorus gettering ; N + oxidation.

Description

technical field [0001] The invention relates to a high-quality shielded diffusion method for a heavily doped silicon substrate, which belongs to the technical field of semiconductors. Background technique [0002] Silicon semiconductor discrete devices and integrated circuits are constantly innovating, and the manufacturing process is also updated and changed accordingly. The collector region, base region and emitter region of the crystal triode are prepared based on the principle of semiconductor impurity diffusion. Usually, semiconductor impurity elements of group III (boron, aluminum, gallium) and group V (phosphorus, arsenic, antimony) are used as doping sources, and N - , N + ,P - P + , N - P + A silicon wafer with a heavily doped deep diffusion junction is used as the substrate for manufacturing power transistors, in which uniform lightly doped N - or P - Conductive type silicon single crystal is used as the collector region to withstand high voltage, and its r...

AI Technical Summary

Problems solved by technology

Its main disadvantage is that the diffusion concentration in the chip will be significantly higher than that in the central area at the edge, which directly affects the consistency of junction depth in the chip, and then affects the consistency of chip parameters.

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